Sunday’s “Game of Thrones” episode, the second in the fourth season, brought the unexpected and gruesome death of King Lannister Baratheon of the House of Lannister. He was poisoned at his wedding and, since then, fans have been wondering who might have done it.

This is no mystery, author George R.R. Martin tells the latest issue of Rolling Stone. The HBO show is based on Martin’s series of novels “A Song of Ice and Fire,” so, if there’s anyone who knows who the culprit behind this is, it must be Martin.

And Martin says that the killer is Olenna Tyrell, aka the Queen of Thorns, Margaery’s grandmother. Margaery was married to Joffrey right before he died so, by all accounts, she is queen. She is an ambitious woman and the Tyrells have high hopes for her but, Martin says, the last thing they wanted was to sacrifice her to a cruel, heartless boy like Joffrey.

Of course, the author notes, there is a chance that writers on the series might take some liberties with the script, so he adds that this is how he wanted it to play out in the books.

“In the books — and I make no promises, because I have two more books to write, and I may have more surprises to reveal — the conclusion that the careful reader draws is that Joffrey was killed by the Queen of Thorns, using poison from Sansa’s hair net, so that if anyone actually did think it was poison, then Sansa would be blamed for it. Sansa had certainly good reason for it,” Martin explains.

He compares killing Joffrey to killing Hitler, and he says that, depending on how you look at it (the Queen of Thorns killed Hitler or she killed a 13-year-old boy), she could be redeemed or not.

“She certainly had good reasons to remove Joffrey. Everything she’d heard about him, he was wildly unstable, and he was about to marry her beloved granddaughter. The Queen of Thorns had studied Joffrey well enough that she knew that at some point he would get bored with Margaery, and Margaery would be maltreated, the same way that Sansa had been. Whereas if she removed him then her granddaughter might still get the crown but without all of the danger. So is that a case where the end justifies the means? I don’t know,” Martin continues.

He hopes fans will open a debate to get the answer to that question. Meanwhile, we know this for certain: Joffrey was a horrible human being who did horrible things to good people. He was also entitled and a coward, he was cruel and annoying. At the same time, Joffrey was also fans’ number 1 love-to-hate character and, for that alone, he will be missed.